vattenkärlsystem

The vattenkärlsystem, or water vascular system, is a unique and complex network involved primarily in the locomotion, feeding, and sensory reception of echinoderms, a phylum that includes sea stars, sea urchins, and sea cucumbers. This system is a characteristic feature of echinoderms and is vital for their interaction with the environment.

The water vascular system consists of a central body cavity connected to a series of coelomic channels, including the madreporite, stone canal, ring canal, and radial canals. The madreporite acts as an entry point for seawater, which is then filtered into the system via the stone canal into the ring canal encircling the central disc. From the ring canal, water is distributed through radial canals extending into each arm (in sea stars or similar appendages). Attached to these canals are numerous tube feet, which are small, flexible, pod-like structures used for movement, attachment, and sometimes respiration.

The system operates through a hydraulic mechanism involving the controlled influx and efflux of seawater, which generates the force necessary for the extension and retraction of the tube feet. This hydraulic system allows echinoderms to navigate their surroundings, capture prey, and interact with surfaces. Additionally, the water vascular system plays a role in chemosensation and environmental sensing.

Given its specialized structure, the water vascular system exemplifies a biological strategy of utilizing fluid pressure for versatile functions. It showcases how echinoderms efficiently operate in their marine environments through hydraulically-based movement and sensory capabilities, contributing to their ecological success and resilience.